Azirine compounds

ABSTRACT

AZIRINE COMPOUNDS OF THE FORMULA:   R1-CO-CH&lt;(-C(-R)=N-)   WHEREIN R IS ALKYL OF C1-C8, PHENYL, OR SUBSTITUTED PHENYL AND R1 IS ALKYL OF C2-C18, PHENYL OR SUBSTITUTED PHENYL, WHERE SAID SUBSTITUENTS ARE MEMBERS SELECTED FROM THE GROUP CONSISTING OF CYANO; HALOGEN; TRIFLUOROMETHYL; ACYLOXY OF THE FORMULA:   R2-COO-   AMIDO OF THE FORMULA:   R3-CO-NH-   AMINO OF THE FORMULA: R4R5N-; ALKOXY OF THE FORMULA: R6O-; ALKYLTHIO OF THE FORMULA; AND ALKYL OF C1-C18; WHERE R2 IS ALKYL OF C1-C8, PHENYL, NAPHTHYL OR HYDROGEN; R3 IS ALKYL OF C1-C8, PHENYL OR NAPHTHYL; R4 AND R5 ARE HYDROGEN OR ALKYL OF C2-C3 AND R6 IS ALKYL OF C1C18, ARE PREPARED BY THE PHOTOTRANSPOSITION OF ISOXAZOLES. THEY ARE USEFUL IN IMAGING. THEY ARE ALSO USEFUL IN INFORMATION STORAGE AND RETRIEVAL.

United States Patent m 3,772,284 AZIRINE COMPOUNDS Balwant Singh, Stamford, Conn., and Edwin Fisher Ullman, Atherton, Calif., assignors to American Cyanamid Company, Stamford, Conn.

No Drawing. (Iontinuation-in-part of abandoned application Ser. No. 603,172, Dec. 20, 1966. This application Apr. 15, 1970, Ser. No. 28,955

Int. Cl. C07d 23/00 U5. Cl. 260-439 A 7 Claims ABSTRACT OF THE DISCLOSURE Azirine compounds of the formula:

wherein R is alkyl of C -C phenyl or substituted phenyl and R is alkyl of C1C18, phenyl or substituted phenyl, where said substituents are members selected from the group consisting of cyano; halogen; trifiuoromethyl; acyloxy of the formula:

R -t'i-O- amido of the formula:

This application is a continuation-in-part of our copending application for Letters Patent, Ser. No. 603,172, filed, Dec. 20, 1966, now abandoned.

The present invention is directed to novel carbonylsubstituted azirine compounds and to a unique method for their preparation from isoxazoles. It further relates to their use for imaging and information storage and retrieval. The azirine compounds are also useful in the preparation of 4-arninopyrazoles.

Photosensitive compounds and compositions play an essential part in photography and the related arts dealing with processes of writing, printing, and producing images. Currently available methods typically involve the use of costly ingredients, such as silver salts, and inconvenient and time consuming processes, such as, fixing images by washing. It is, therefore, an object of the present invention to provide novel photosensitive compounds and compositions which are capable of forming images by processes which overcome one or more of the above limitations.

Information storage and recovery systems are of rapidly increasing importance in the present-day economy in view of the exponential rise in the number and complexity of the data which must be recorded and be retrievable to handle the increasing every-day business load, and to assist in scientific developments. Many optical systems, including those based on silver halide emulsions and the like, have contributed significantly to this development, largely because of the high packing density with good retrievable resolution inherent in such systems. Systems based on magnetic means, e.g., the well-known magnetic tape and magnetic ink check-printing systems, have likewise found great utility, largely because of the relative ease of 3,772,284? Patented Nov. 13, 1973 handling and the relatively simple equipment involved, combined with, particularly in the case of the tapes, high reproducible fidelity. However, the optical systems are not as versatile as desired in that only a single image is normally recorded at any one bit, e.g., the developed Ag image. The same is true of the magnetic tape images where normally only the magnetic image is obtained at any one bit. This image can be made visual by a separate step, e.g., by dusting with iron powder. The magnetic ink images have the advantage of being both visually and magnetically sensible; however, these images suffer from a relatively low packing density. It is, therefore, another object of the present invention to provide novel photosensitive compounds, compositions and processes which are capable of information storage and recovery, overcoming one or more of the above-disadvantages. These and other objects will become apparent from the following description.

The carbonyl-substituted azirine compounds of the present invention are graphically represented by Formula II. They are conveniently prepared by means of a phototransposition of the isoxazole compounds of Formula I. The reaction scheme is graphically depicted as follows:

wherein R is alkyl of C -C phenyl or substituted phenyl and R is alkyl of C C phenyl or substituted phenyl, where said substituents are members selected from the group consisting of cyano, halogen; trifluoromethyl; acyloxy of the formula:

amido of the formula:

depicted as follows:

0 N N II 2 A CR 1 R III wherein R and R are as defined above.

The photolysis reactions shown above are uniquely de pendent on the wavelength of the light used to irradiate the materials. Thus, it has been discovered that the isoxa- Zole (I) is formed by irradiation of azirine (II) with light of wavelength longer than 3130 A. and preferably near 3341 A. At 3130 A. or shorter wavelength light the azirine (II) converts to oxazole (III). Any wavelength of light which is absorbed by isoxazole (I) will serve to convert it to azirine (II). The precise Wavelengths are dependent on the nature of substituents R and R For example, when R and R are phenyl, 2537 A. light readily converts (I) to (II) and (II) to (III). As a general rule, therefore, broad spectrum light will convert (I) to (II) but wavelengths less than 3130 A. are preferred to maximize formation of the azirine.

The photolysis reactions are conveniently conducted by dissolving the isoxazole (I) in an inert organic solvent, such as diethyl ether, benzene, tetrahydrofuran, cyclohexane, ethyl acetate, acetonitrile, and the like, and irradiating the solution; usually at room temperature (about 20 C.) but at reduced or elevated temperatures if desired, with light of the requisite wavelength and intensity. High pressure mercury vapor or xenon lamps are useful for this purpose. Before irradiation it is desirable but not critical to bubble an inert gas such as nitrogen through the solution to provide an inert atmosphere above the solution.

The reaction is conveniently followed by sampling at intervals and analyzing the samples by ultraviolet spectroscopy. To obtain maximum yield of azirine (II) the reaction must be closely followed. This is facilitated, of course, by controlling the wavelength of the irradiation and by interrupting the reaction for sampling. Product azirine is isolated by standard procedures such as chromatography and crystallization.

Reaction time depends on the amounts of reactant in solution, intensity of the light and other such non-critical factors. Accordingly, photolysis may be accomplished in several minutes or several days as desired.

For imaging and information storage and retrieval, a photosensitive composition is prepared by coating a conventional photographic substrate with either the isoxazoles of Formula I or preferably of the azirines of Formula II. The composition is then exposed to an information containing beam of ultraviolet light, of suflicient intensity and duration to cause a phototransposition to an isoxazole (III) in the exposed areas of the composition. The resulting colorless image is made visible by then exposing the composition to near ultraviolet light having a frequency of from about 3300 to 3600 A. The resulting blue fluorescent image can be visually detected or machine read in an automated process.

It will be understood that the information formed may be of any desired type, such as, for example, alphanumeric characters, code markings, such as dots or lines, or pictorial information. The image can be formed in any well known manner, such as by focusing a radiant beam, projecting a beam through a stencil, template or film negative or by use of a moving mirror system with lasers and the like. The exposure time will depend on such factors as the intensity of the radiation source, the particular composition being used and the intensity of the image desired. Generally, periods of exposure in the range k of nanoseconds to milliseconds is sufficient to obtain detectable, fluorescent emission.

In the present invention, storage of information is rapid, accurate and dry, no fixing being required. Retrieval is rapid, exceptionally sensitive and accurate and is not accompanied by degradation. The inventive technique combines optical deposition of information, causing photochemical reaction in irradiated areas, thus allowing fine resolution, with detection by fluorescence (more sensitive than absorption). As mentioned, no fixing is required where the fluorescer precursor is only sensitive to light of wavelength of less than the detecting beam of radiation. Moreover, it is possible to obtain high information density packing with the present invention.

The inventive method may be used to replace any process that employs change of optical density to change an electrical signal. This may include electronic storage and replay of sound and pictures, numerical data collection and retrieval, and the like; and to produce and validate cards, stamps, passes, and the like documents.

Since the fluorescer precursor is a colorless material, the storage and retrieval may be unknown to all persons except those intended to have knowledge of the informa tion storage. This could be used for placing information on passes or documents to be retained by one person and checked or authenticated by another, such as in the case of a gate pass. An advantage of the present system is that any portion or the entire cards or documents can be treated with the fluorescer precursor, even over other information or images, after which particular information may be put on the treated part by light projection. It will be apparent, therefore, that many cards may be produced, with individual information placed thereon at a later time, by conversion of the desired image portion to a fluorescent compound. Since the compounds are colorless in either state, space is saved in that the latter information is printed over the original visible information. Detection is preferably as previously indicated, by means of a longer wavelength of light which stimulates the fluorescent form of the material. This stimulating radiation is of such a wavelength that it does not convert any of the remaining photosensitive materials. Although this is the preferable mode of operation in order to prevent conversion of the background to the same state as the image, where the detection is relatively of short duration, this could be done by the same wavelength radiation as used to form the image.

The present material has a further characteristic that the amount of detectable fluorescence is proportional to the amount of latent fluorescer which has been converted to the fluorescent state. The amount converted on any radiated area depends on the duration of time of exposure to the irradiating energy. The longer the time period is, the more latent fluoresccer there will be converted per unit of exposed area and thus the more intense the fluorescence upon subsequent radiation and detection. This characteristic makes it possible to produce detectable variable tone fluorescent radiation over a given area. This is much like the tone variation in a photographic negative or a magnetic sound tape. Thus the present invention could be used to prepare a sound tape by audio modulation of the radiant source. The sound is detectable by conventional fluorescent detection means coupled to audio output means by a suitable transducer. A sound track could be put on a movie film in the same manner, either beside the picture, or printed directly on the film. A phonograph disc could be prepared and played on the same principle.

Although the intensity of fluorescence increases with exposure to radiation, detectable radiation has been obtained with a low intensity light source at as low as one millisecond and with a laser, imaging may be done in nanoseconds.

While the converted fluorescent information cannot be removed, it would be possible to insert new information by blotting an old word or number by converting it entirely to a fluorescent bar, and creating another word or number adjacent thereto in fluorescer precursor material. This, of course, is limited to the area of treatment with fluorescer precursor material.

The fluorescer precursor material may be coated on any desired substrate, or it may be incorporated in transparent or opaque plastic films. The substrate may be of any configuration, i.e., sheets, belts, discs, drums, three dimen sional objects such as bottles, boxes, and the like. Techniques for this will be readily apparent to persons skilled in the art. It will be obvious that choice of materials may depend on the particular intended use.

The azirine compounds of Formula II are useful as intermediates in the preparation of 4-aminopyrazoles (IV). The general reaction scheme is graphically depicted as follows:

0 II IU-C N HzN- Hydrazine Acid Salt C CR II H IV The preparation is effected by reacting an azirine compound with a hydrazine acid salt having the formula:

where A is a mineral acid, such as, perchloric acid, hydrochloric acid, sulfuric acid, and the like. All inert solvent in which all of the reactants are soluble, such as water, methanol, ethanol, dioxane, tetrahydrofuran, and the like, including mixtures thereof when practical, is advantageously employed.

Reaction is essentially complete in about fifteen minutes at about 60 C. but may also be effected at or below room temperature or up to 100 C. or higher depending on proportions of reactants and solvent medium. Substantially equimolecular proportions of reactants are employed although excesses of either reactant is also useful. Generally, the reacted solution is neutralized with a suitable base such as sodium bicarbonate, potassium carbonate, sodium hydroxide, triethylamine, and the like, and the product separated by conventional procedures such as solvent extraction, and further purified by recrystallization. It is believed that the carbonyl function is important for formaof the azirine by the acid of the hydrazine salt followed by opening of the ring by attack of the hydrazine.

These and other conditions of reaction, such as pressure and sequence of addition, are not critical and may be varied as desired.

As far as is known the azirine compounds of the invention are the first such compounds containing a carbonyl and an aromatic function on the azirine ring. It is believed that the carbonyl function is important for formation of the 4-aminopyrazole end product and that the aromatic function serves to stabilize the double bond in the azirine.

The 4-aminopyrazoles (IV) are useful in compositions also containing an aromatic amine compound and a compound which is a source of halogen. When irradiated with ultraviolet light, the compositions become intensely colored, ranging from blue to violet depending primarily on the choice of aromatic amine. The compositions are, therefore, valuable in applications dependent on photosensitivity such as photocopying. For example, a composition may be prepared by dissolving equimolar amounts of 4- amino-3,S-diphenylpyrazole and diphenylamine in chloroform. The solution is then emulsified and applied to paper. When the coated paper is dried and exposed to ultraviolet light transmitted through or reflected from a surface containing information to be copied (master), the coated paper becomes colored in patterns duplicating the information on the master. Photosensitive compositions of this type are disclosed in copending US. patent application Ser. No. 603,171 which is incorporated herein by reference.

The isoxazole compounds of Formula I are well known in the chemical literature. They may be prepared by a variety of synthetic methods such as those set forth in Heterocyclic Compounds, R. H. Wiley, pp. 16-20 (1962), Interscience Pub. Suitable isoxazole compounds of Formula I include, for example:

3-methy1-S- phenylisoxazole, 3-phenyl-S-methylisoxazole, 3-phenyl-S-n-butylisoxazole, 3-phenyl-S-n-octylisoxazole, 3-phenyl-S-p-acetoxyphenylisoxazole, 3-phenyl-S-p-dimethylaminophenylisoxazole, S-phenyl-S-(p-acetaminophenyl)isoxazole, 3-nbutyl-5-phenylisoxaz0le, 3-n-octyl-5-phenylisoxazole, 3-methyl-5-octadecylisoxazole,

3- p-cyanophenyl -5 -phenylisoxazole, 3-(o-p-dichlorophenyl)-5-phenylisoxazole, 3-(p-trifiuoromethylphenyl)5-methylisoxazole, 3 (p-fo rmyloxyphenyl -5-methylisox azole,

3- [4'- (alphanaphthoyloxy) phenyl] -5-methylisoxazole, 3- (o-benzoyloxyphenyl) -5-phenylisoxazole, 3-(p-acetoxyphenyl)-5-phenylisoxazole,

3- (p-acetamidophenyl) -5-methylisoxazole, 3-(p-benzamidophenyl)-5-methylisoxazole,

3- [4'- (alpha-naphthamido phenyl] -5-phenylisoxazole, 3 (o-aminophenyl) -5-methylisoxazole,

3- (m-aminophenyl -5-phenylisoxazole,

3- [p- (N,N-dimethylamino phenyl] -5-phenylisoxazole, 3- [p- (N-ethylamino phenyl -5-phenylisoxazo1e,

3- (o-methoxyphenyl) -5-methy1isoxazole,

3- (p-octadecyloxyphenyl) -5-phenylisoxazole,

3- (p-methylphenyl) -5-methylisoxazole,

3- (p-octadecylphenyl -5-phenylisoxazole,

3- o-thiomethoxyphenyl -5-phenylisoxazole,

3- (p-thiooctadecyloxyphenyl -5methylisoxazole, 3-n-octyl-5 m-cyanophenyl isoxazole,

3-n-butyl-5- (p-bromophenyl isoxazole,

3-phenyl-5- (p-trifluoromethylphenyl) isoxazole, 3-methyl-5- (p-formyloxyphenyl) isoxazole, 3-phenyl-5- (o-acetoxyphenyl) isoxazole,

3 -ethyl-5-[4- (alpha-naphthoyloxy) pheny11isoxazole, 3 -phenyl-5 (p-benzyloxyphenyl isoxazole, 3-methyl-5- (o-acetamidophenyl) isoxazole, 3-phenyl-S- (p-benzamidophenyl isoxazole,

3-ethyl-5- alpha-naphthamidophenyl isoxazole,

3 -phenyl-5 (m-aminophenyl isoxazole,

3-ethyl-5- [p- (N,N-dimethylamino) phenyl] isoxazole, 3-phenyl-5- (p pentyloxyphenyl) isoxazole,

3-ethyl-5- (p-thiomethyloxyphenyl isoxazole and 3 -phenyl-5- (p-propylphenyl isoxazole.

The invention is further illustrated but not limited by the following examples. All parts and percentages are by weight unless otherwise indicated.

EXAMPLE 1 3-benzoyl-2-methyll-azirine A mixture of benzoylacetone (4.69 g., 0.0617 mole) and hydroxylamine hydrochloride (4.69 g., 0.0678 mole) and 50 ml. of ethanol was refluxed for 4 hours. The ethanol was removed in vacuo and the residue extracted with benzene. The benzene extract was dried (MgSO and evaporated to yield 10 g. of a colorless solid (M.P. 60- 64). Recrystallization from 50% aqueous ethanol yielded colorless crystals of 3-methyl-5-phenylisoxazole (7.0 g.) M.P. 63-64 C., lit. M.P. 65.5-66 C.

A solution of 1.0 g. of 3-methyl-5-phenyl isoxazole in 100 ml. of benzene was bubbled with nitrogen and irradiated with 3000 A. light in the Rayonet reactor for 24 hours. Removal of benzene in vacuo left a residue which was dissolved in hexane-ether (3: 1) and chromatographed over silica gel. The unreacted isoxazole and any oxazole formed was removed in the fractions (1-11) using 3:1 hexane-ether as an eluent. Fractions 13-16 contained the desired azirine compound.

EXAMPLE 2 3-benzoyl-2 phenyl-1-azirine A solution of dibenzoyl methane (4.48 g., 0.22 mole) in 180 ml. of methanol was treated with a solution of hydroxylamine hydrochloride (2.76 g., 0.04 mole) in 10 m1. of water. Sodium acetate (3.2 g., 0.04 mole) was added and the mixture heated under reflux until the enol test with alcoholic FeCl was negative (-6 hours). The reaction mixture was diluted with water and cooled. The precipitated solid was filtered, washed with dilute methanol and dried. Recrystallization from ethanol furnished 4.1 g. (90%) of 3,5-diphenylisoxazole as shining white plates (M.P. 141, lit. M.P. 141).

A solution of 3,5-diphenylisoxazole (670 milligrams) in 200 milliliters of benzene was placed'in a suitable flask. The solution, after bubbling with nitrogen for a few minutes, was then irradiated with broad spectrum light (Hanovia watt medium pressure U-shaped mercury vapor arc) for 30 hours. Removal of the solvent left a light-yellow residue whose infrared spectrum showed bands at 5.63 and 599 in addition to the bands due to the isoxazole. Chromatography of the mixture on silica gel yielded 237 milligrams of 3,5-diphenylisoxazole plus a nearly colorless oil identified by ultraviolet and infrared spectra as 3-benzoyl-2-phenyl-l-azirine (250 milligrams, 38%).

Analysis.Calcd for C H NO (percent): C, 81.43; H, 5.01; N, 6.33. Found (percent): C, 81.26; H, 5.36; N, 6.41. M01 wt. 221 (mass spectrometer).

EXAMPLE 3 Transformation of 3-benzoyl-2-phenyl-1-azirine to 2,5-diphenyl-oxazole A sample of the azirine (38 mg.) in 20 ml. of anhydrous ether (bubbled with N was irradiated with light (2537 A.). The reaction was followed by ultraviolet spectroscopy. When the starting material had almost disappetred, the reaction was stopped. Removal of ether left a light yellow solid which was chromatographed over silica gel. Elution with petroleum ether-ether (20:1) yielded a white crystalline solid, M.P. 7374. (21.3 mg), identified as 2,5-diphenyloxazole. Elution with petroleum etherether (10:1) yielded 11 mg. of the unchanged material.

EXAMPLE 4 Transformation of 3-benzoyl-2-phenyl-l-azirine to 3,5-diphenyl-isoxazole A solution of the azirine (80 mg.) in 50 ml. of ether (bubbled with N was irradiated for 4 hours in a Pyrex flask With light 3000 A.). The solvent was removed under reduced pressure and the residue chromatographed over silica gel. Elution with benzene yielded 3,5-diphenylisoxazole (I) (68 mg, 85% Elution with benzene-ether (50: 1) gave 14 mg. of the unchanged azirine.

EXAMPLE 5 Spectroscopic examination of the transformation of 3,5-diphenylisoxazole to 2,5-diphcnyloxazole A solution of 3,5-diphenylisoxazole in anhydrous ether (5.45 X M) was placed in a quartz cell. The solution was irradiated with 2537 A. light and the ultraviolet spectrum was recorded after every 5 minutes. After 35 minutes the concentration of 2,5-diphenyloxazole had reached a maximum representing an 85 conversion.

EXAMPLE 6 3-acetyl-2-pheny1- l-azirine A sample of the 2-hydroxylaminobutyrophenone oxime g.) was heated at 160 for 1 hour and the residue distilled. The oil distilling at 123 130/10 mm. was collected (26 g.). The oil was dissolved in 30 ml. of cone.

HCl and the solution diluted with 25 ml. of water. A solid crystallized (10 g.) and was recrystallized from petroleum ether to yield a colorless solid 6.5 g. M.P. 40-41". Lit. M.P. 4041".

A sample of 3-phenyl-S-methyl isoxazole (400 mg.) in 150 ml. of n-hexane was irradiated for 2.5 hours in a quartz cell with 2537 A. light in a Rayonet reactor. The soution was concentrated and chromatographed over silica gel. Elution with hexane-ether (5: 1) removed the oxazole. Hexane-ether (3: 1) eluted the desired azirine compound (100 mg.).

A solution of 3-p-anisyl-5-phenyl isoxazole (1 gram) in 150 milliliters of benzene was bubbled with nitrogen for several minutes and then irradiated for 20 hours with ultraviolet light. Removal of benzene left a light-yellow residue. The mixture was chromatographed over silica gel to give unreacted starting material and 3-benzoyl-2-p anisyl-l-azirine milligrams) which solidified on scratching. Recrystallization of the azirine from ether furnished colorless prisms, melting point 8990 C. The azirine was further identified as 3-benzoyl-2-p-anisyl-1-azirine by infrared and ultraviolet spectroscopy.

AnaIysis.-Calcd for C H O N (percent): C, 76.47; H, 5.22; N, 5.57 Found (percent): C, 76.65; H, 5.45; N, 5.82.

8 EXAMPLES 7-4s Table I illustrates other azirine compounds of the invention which are prepared from the appropriate isoxazoles and are converted to oxazoles substantially as described in Examples 1 through 6 above. R and R of the table correspond to the substituents of generic Formulae II and III.

We claim: 1. An azirine compound of the formula:

ll R1C(IJ H wherein R is phenyl or substituted phenyl and R is alkyl of C -C phenyl or substituted phenyl, where said substituents are members selected from the group consisting of cyano; halogen; trifiuoromethyl; acyloxy of the formula:

II R -OO;

amido of the formula:

ll R3-CNH;

9 10 7. An azirine compound of the formula: phenyl or naphthyl; and R and R are hydrogen or alkyl 0 N Of C1-C8.

h b d h l d 1 1k 1 5 UNITED STATES PATENTS wherein R is p enyl or su stitute p eny an R is a y of C C phenyl or substituted phenyl, where said sub- 3497351 2/1970 Harvey 260 239 stituents are members selected from the group consisting ALTON ROLLINS Primary Examiner of halogen; amido of the formula:

e 10 U.S. Cl. X.R. R -C-NH; 96-1 R, 27 F, 48 HC, 90 PC; 117--33.5; 204158 R;

amino of the formula: R R N-; alkoxy of the formula: 260-307 R, 307 310 R R O--; and alkyl of C -C where R is alkyl of C -C 

